Various bodily functions operate at frequencies that are harmonics or sub-harmonics of the brain's intrinsic frequency. For example, the heart rate is approximately the 8th or 9th sub-harmonic of the brain's alpha frequency at awake and 2nd or 3rd sub-harmonic of delta at sleep. The breathing rate is the 5th sub-harmonic of the heartbeat which is why the standard CPR procedure requires 5 heart compressions for each breath although some now recommend that only compressions be administered to CPR recipients. The gastrointestinal movement frequency is approximately the 4th or 5th sub-harmonic of the breathing rate.
Transcranial magnetic stimulation (TMS) is a procedure that uses magnetic fields to stimulate nerve cells in the brain to improve symptoms of depression and other neuropsychiatric conditions. Traditionally, TMS coils have been of a circular or figure-8 shape, designed to achieve maximum strength at a single point. For treatment of depression with transcranial magnetic stimulation, a large electromagnetic coil is placed against or near the scalp near the forehead. The electromagnet used in transcranial magnetic stimulation creates electric currents and magnetic fields that stimulate nerve cells in the region of the brain involved in mood control and depression.
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive, non-surgical method to excite neurons in the brain. Weak electric currents are induced in brain tissues by rapidly changing electro-magnetic fields through electromagnetic induction. Brain activity is triggered and modulated without the need for surgery or external electrodes. In particular, alpha brain waves can be modulated in a desirable manner.
In an rTMS device, current is generated through a wire to a main coil where an electromagnetic field is induced with direction perpendicular to that of the flat surface of the coil. The coil is placed against or in close proximity to specific areas of the patient's head/scalp corresponding to brain regions underneath the skull that are the target of treatment. The electromagnetic field resulting from the current in the coil penetrates the skull and stimulates brain areas underneath, potentially exciting neurons at predetermined frequencies. rTMS/TMS has several effects, stimulating brain structures according to coil placement, changing neuron firing rates, and adjusting blood-flow in the brain. The rTMS device emits a distinctive clicking sound which the patient can hear during an rTMS treatment. Additionally, the patient receiving an rTMS treatment will experience a tapping sensation in their head adjacent to the magnet coils of the rTMS device. rTMS treatment plans are generally started on a daily treatment basis, usually Monday-Friday, although continuous daily treatments can also be employed. After the patient exhibits a noticeable relief in symptoms or a desirable modulation of brain wave activities then the daily treatment are usually reduced gradually to an intermittent treatment regime such as once or twice a week to biweekly to monthly treatments.
It has been unexpectedly discovered that a mental disorder or a physical function in a patient can be treated or improved by subjecting the patient to a sensory stimulation at a frequency of a biological metric or a harmonic thereof. It has also been unexpectedly discovered that patients who have been successfully treated with rTMS develop a Pavlovian response (conditional response) to the clicking sound of the rTMS machine. This conditional response can be utilized in the continued treatment of the patients by subjecting the patients to an audio sound similar to the clicking sound emitted by the rTMS machine to produce a therapeutic effect which can reduce the number of costly rTMS treatments.